Rifamycin Disease Interactions

Clostridioides difficile-associated diarrhea (CDAD), formerly pseudomembranous colitis, has been reported with almost all antibacterial drugs and may range from mild diarrhea to fatal colitis. The most common culprits include clindamycin and lincomycin. Antibacterial therapy alters the normal flora of the colon, leading to overgrowth of C difficile, whose toxins A and B contribute to CDAD development. Morbidity and mortality are increased with hypertoxin-producing strains of C difficile; these infections can be resistant to antimicrobial therapy and may require colectomy. CDAD must be considered in all patients who present with diarrhea after antibacterial use. Since CDAD has been reported to occur more than 2 months after antibacterial use, careful medical history is necessary. Therapy with broad-spectrum antibacterials and other agents with significant antibacterial activity should be administered cautiously in patients with history of gastrointestinal disease, particularly colitis; pseudomembranous colitis (generally characterized by severe, persistent diarrhea and severe abdominal cramps, and sometimes associated with the passage of blood and mucus), if it occurs, may be more severe in these patients and may be associated with flares in underlying disease activity. Antibacterial drugs not directed against C difficile may need to be stopped if CDAD is suspected or confirmed. Appropriate fluid and electrolyte management, protein supplementation, antibacterial treatment of C difficile, and surgical evaluation should be started as clinically indicated.

The use of rifamycin has not been demonstrated to be effective in the treatment of travelers' diarrhea caused by pathogens other than E. coli. Treatment with this agent has not shown to be effective in patients with diarrhea complicated by fever and/or bloody stools. Rifamycin is not recommended for use in patients with diarrhea accompanied by fever or bloody stools or due to pathogens other than noninvasive strains of E. coli. It is recommended to discontinue therapy if diarrhea gets worse or persists more than 48 hours and to consider alternative antibacterial therapy.

The pharmacokinetics of rifamycin in patients with impaired hepatic function have not been studied. Rifamycin has limited systemic exposure after oral administration; therefore, it is not expected to necessitate a dose adjustment in patients with liver dysfunction. Close monitoring is recommended.

The pharmacokinetics of rifamycin in patients with impaired renal function have not been studied. Rifamycin has limited systemic exposure after oral administration and minor role of renal excretion in elimination of rifamycin; therefore, it is not expected to necessitate a dose adjustment in patients with impaired renal function. Close monitoring is recommended.